scholarly journals Novel Polymeric Nanocarriers Reduced Zinc and Doxycycline Toxicity in the Nematode Caenorhabditis elegans

Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 550 ◽  
Author(s):  
Manuel Toledano ◽  
Manuel Toledano-Osorio ◽  
María D. Navarro-Hortal ◽  
Alfonso Varela-López ◽  
Raquel Osorio ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Caenorhabditis Elegans ◽  
Death Rate ◽  
Polymeric Nanoparticles ◽  
Model Organism ◽  
Polymeric Nanocarriers ◽  
Pharyngeal Pumping ◽  
Species Production ◽  
Intracellular Hydrogen Peroxide

The objective was to evaluate the toxicity of zinc- and doxycycline-loaded polymeric nanoparticles (NPs) using Caenorhabditis elegans as a model organism. These NPs are composed of ethylene glycol dimethacrylate, 2-hydroxyethyl methacrylate and methacrylic acid. NPs were loaded with doxycycline (D-NPs) and zinc (Zn-NPs) by chemical adsorption, and loading efficacy was demonstrated. Worm death rate in a concentration-response curve basis was calculated for lethality. Metabolism was evaluated through pharyngeal pumping assay. Body length measurements, brood size and egg lays were used to gauge growth, reproduction and fertility respectively. Intracellular hydrogen peroxide levels were determined to assess the reactive oxygen species production. One-way ANOVA and Bonferroni were used for comparisons (p < 0.05). Tested NPs at the highest dosage did not affect lethality or worm metabolism, expressed in terms of death rate and pharyngeal pumping per minute, respectively. Zn-NPs slightly increased worm growth. The concentration of the intracellular hydrogen peroxide levels was the lowest in the D-NPs group. The distinct NPs and concentrations employed were shown to be non-toxic for in situ administration of zinc and doxycycline, reducing the harmful effects of these compounds.

scholarly journals Hydrogen Peroxide-Mediated Killing of Caenorhabditis elegans by Streptococcus pyogenes

2002 ◽  
Vol 70 (9) ◽  
pp. 5202-5207 ◽  
Author(s):  
W. T. M. Jansen ◽  
M. Bolm ◽  
R. Balling ◽  
G. S. Chhatwal ◽  
R. Schnabel
Keyword(s):  
Hydrogen Peroxide ◽  
Caenorhabditis Elegans ◽  
Streptococcus Pyogenes ◽  
Wide Spectrum ◽  
Model Organism ◽  
Common Mechanism ◽  
Gram Positive ◽  
C Elegans ◽  
Gram Positive Bacteria ◽  
Serovar Typhimurium

ABSTRACT Caenorhabditis elegans is currently introduced as a new, facile, and cheap model organism to study the pathogenesis of gram-negative bacteria such as Pseudomonas aeruginosa and Salmonella enterica serovar Typhimurium. The mechanisms of killing involve either diffusible exotoxins or infection-like processes. Recently, it was shown that also some gram-positive bacteria kill C. elegans, although the precise mechanisms of killing remained open. We examined C. elegans as a pathogenesis model for the gram-positive bacterium Streptococcus pyogenes, a major human pathogen capable of causing a wide spectrum of diseases. We demonstrate that S. pyogenes kills C. elegans, both on solid and in liquid medium. Unlike P. aeruginosa and S. enterica serovar Typhimurium, the killing by S. pyogenes is solely mediated by hydrogen peroxide. Killing required live streptococci; the killing capacity depends on the amount of hydrogen peroxide produced, and killing can be inhibited by catalase. Major exotoxins of S. pyogenes are not involved in the killing process as confirmed by using specific toxin inhibitors and knockout mutants. Moreover, no accumulation of S. pyogenes in C. elegans is observed, which excludes the involvement of infection-like processes. Preliminary results show that S. pneumoniae can also kill C. elegans by hydrogen peroxide production. Hydrogen peroxide-mediated killing might represent a common mechanism by which gram-positive, catalase-negative pathogens kill C. elegans.

scholarly journals Acute exposure to a glyphosate-containing herbicide formulation inhibits Complex II and increases hydrogen peroxide in the model organism Caenorhabditis elegans

2019 ◽  
Vol 66 ◽  
pp. 36-42 ◽  
Author(s):  
Shelbie L. Burchfield ◽  
Denise C. Bailey ◽  
Callie E. Todt ◽  
Rachel D. Denney ◽  
Rekek Negga ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Caenorhabditis Elegans ◽  
Model Organism ◽  
Acute Exposure ◽  
Complex Ii

scholarly journals Modulation of Macrophages M1/M2 Polarization Using Carbohydrate-Functionalized Polymeric Nanoparticles

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 88
Author(s):  
Raquel G. D. Andrade ◽  
Bruno Reis ◽  
Benjamin Costas ◽  
Sofia A. Costa Lima ◽  
Salette Reis
Keyword(s):  
Inflammatory Responses ◽  
Polymeric Nanoparticles ◽  
Interaction Mechanism ◽  
Mannose Receptor ◽  
The Body ◽  
Receptor Expression ◽  
Production Methods ◽  
Polymeric Nanocarriers ◽  
Efficient Delivery

Exploiting surface endocytosis receptors using carbohydrate-conjugated nanocarriers brings outstanding approaches to an efficient delivery towards a specific target. Macrophages are cells of innate immunity found throughout the body. Plasticity of macrophages is evidenced by alterations in phenotypic polarization in response to stimuli, and is associated with changes in effector molecules, receptor expression, and cytokine profile. M1-polarized macrophages are involved in pro-inflammatory responses while M2 macrophages are capable of anti-inflammatory response and tissue repair. Modulation of macrophages’ activation state is an effective approach for several disease therapies, mediated by carbohydrate-coated nanocarriers. In this review, polymeric nanocarriers targeting macrophages are described in terms of production methods and conjugation strategies, highlighting the role of mannose receptor in the polarization of macrophages, and targeting approaches for infectious diseases, cancer immunotherapy, and prevention. Translation of this nanomedicine approach still requires further elucidation of the interaction mechanism between nanocarriers and macrophages towards clinical applications.

scholarly journals A novel Keap1 inhibitor iKeap1 activates Nrf2 signaling and ameliorates hydrogen peroxide-induced oxidative injury and apoptosis in osteoblasts

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Yue-huan Zheng ◽  
Jian-jun Yang ◽  
Pei-jun Tang ◽  
Yuan Zhu ◽  
Zhe Chen ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Nuclear Translocation ◽  
Oxidative Injury ◽  
Potential Effect ◽  
Protein Stabilization ◽  
Human Osteoblasts ◽  
Nrf2 Knockout ◽  
Anti Oxidant ◽  
Species Production ◽  
Nrf2 Protein

AbstractAn ultra-large structure-based virtual screening has discovered iKeap1 as a direct Keap1 inhibitor that can efficiently activate Nrf2 signaling. We here tested its potential effect against hydrogen peroxide (H2O2)-induced oxidative injury in osteoblasts. In primary murine and human osteoblasts, iKeap1 robustly activated Nrf2 signaling at micromole concentrations. iKeap1 disrupted Keap1-Nrf2 association, causing Nrf2 protein stabilization, cytosol accumulation and nuclear translocation in murine and human osteoblasts. The anti-oxidant response elements (ARE) activity and transcription of Nrf2-ARE-dependent genes (including HO1, NQO1 and GCLC) were increased as well. Significantly, iKeap1 pretreatment largely ameliorated H2O2-induced reactive oxygen species production, lipid peroxidation and DNA damage as well as cell apoptosis and programmed necrosis in osteoblasts. Moreover, dexamethasone- and nicotine-induced oxidative injury and apoptosis were alleviated by iKeap1. Importantly, Nrf2 shRNA or CRISPR/Cas9-induced Nrf2 knockout completely abolished iKeap1-induced osteoblast cytoprotection against H2O2. Conversely, CRISPR/Cas9-induced Keap1 knockout induced Nrf2 cascade activation and mimicked iKeap1-induced cytoprotective actions in murine osteoblasts. iKeap1 was ineffective against H2O2 in the Keap1-knockout murine osteoblasts. Collectively, iKeap1 activated Nrf2 signaling cascade to inhibit H2O2-induced oxidative injury and death of osteoblasts.

scholarly journals Au Modified F-TiO2 for Efficient Photocatalytic Synthesis of Hydrogen Peroxide

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3844
Author(s):  
Lijuan Li ◽  
Bingdong Li ◽  
Liwei Feng ◽  
Xiaoqiu Zhang ◽  
Yuqian Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction System ◽  
Reaction Medium ◽  
Pure Tio2 ◽  
H2o2 Production ◽  
Tio2 Photocatalyst ◽  
H2o2 Decomposition ◽  
Spin Resonance ◽  
Photocatalytic Synthesis

In this work, Au-modified F-TiO2 is developed as a simple and efficient photocatalyst for H2O2 production under ultraviolet light. The Au/F-TiO2 photocatalyst avoids the necessity of adding fluoride into the reaction medium for enhancing H2O2 synthesis, as in a pure TiO2 reaction system. The F− modification inhibits the H2O2 decomposition through the formation of the ≡Ti–F complex. Au is an active cocatalyst for photocatalytic H2O2 production. We compared the activity of TiO2 with F− modification and without F− modification in the presence of Au, and found that the H2O2 production rate over Au/F-TiO2 reaches four times that of Au/TiO2. In situ electron spin resonance studies have shown that H2O2 is produced by stepwise single-electron oxygen reduction on the Au/F-TiO2 photocatalyst.

Effects of hydrogen peroxide and hypochlorite on membrane potential of mitochondria in situ in rat heart cells

1991 ◽  
Vol 69 (11) ◽  
pp. 1705-1712 ◽  
Author(s):  
Noburu Konno ◽  
K. J. Kako
Keyword(s):  
Hydrogen Peroxide ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Rat Heart ◽  
Mitochondrial Membrane ◽  
Isolated Rat Heart ◽  
Heart Mitochondria ◽  
High Concentrations ◽  
Isolated Rat

Hydrogen peroxide (H2O2) and hypochlorite (HOCl) cause a variety of cellular dysfunctions. In this study we examined the effects of these agents on the electrical potential gradient across the inner membrane of mitochondria in situ in isolated rat heart myocytes. Myocytes were prepared by collagenase digestion and incubated in the presence of H2O2 or HOCl. Transmembrane electrical gradients were measured by distribution of [3H]triphenylmethylphosphonium+, a lipophilic cation. The particulate fraction was separated from the cytosolic compartment first by permeabilization using digitonin, followed by rapid centrifugal sedimentation through a bromododecane layer. We found that the mitochondrial membrane potential (161 ± 7 mV, negative inside) was relatively well maintained under oxidant stress, i.e., the potential was decreased only at high concentrations of HOCl and H2O2 and gradually with time. The membrane potential of isolated rat heart mitochondria was affected similarly by H2O2 and HOCl in a concentration- and time-dependent manner. High concentrations of oxidants also reduced the cellular ATP level but did not significantly change the matrix volume. When the extra-mitochondrial free calcium concentration was increased in permeabilized myocytes, the transmembrane potential was decreased proportionally, and this decrease was potentiated further by H2O2. These results support the view that heart mitochondria are equipped with well-developed defense mechanisms against oxidants, but the action of H2O2 on the transmembrane electrical gradient is exacerbated by an increase in cytosolic calcium. Keywords: ATP, calcium, cardiomyocyte, cell defense, mitochondrial membrane potential, oxidant, triphenylmethylphosphonium.

Behavioral Effects of Volatile Anesthetics in Caenorhabditis elegans

1996 ◽  
Vol 85 (4) ◽  
pp. 901-912 ◽  
Author(s):  
Michael C. Crowder ◽  
Laynie D. Shebester ◽  
Tim Schedl
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Time Course ◽  
Model Organism ◽  
Volatile Anesthetic ◽  
Volatile Anesthetics ◽  
Effective Concentration ◽  
Forward Genetics ◽  
C Elegans ◽  
Median Effective Concentration

Background The nematode Caenorhabditis elegans offers many advantages as a model organism for studying volatile anesthetic actions. It has a simple, well-understood nervous system; it allows the researcher to do forward genetics; and its genome will soon be completely sequenced. C. elegans is immobilized by volatile anesthetics only at high concentrations and with an unusually slow time course. Here other behavioral dysfunctions are considered as anesthetic endpoints in C. elegans. Methods The potency of halothane for disrupting eight different behaviors was determined by logistic regression of concentration and response data. Other volatile anesthetics were also tested for some behaviors. Established protocols were used for behavioral endpoints that, except for pharyngeal pumping, were set as complete disruption of the behavior. Time courses were measured for rapid behaviors. Recovery from exposure to 1 or 4 vol% halothane was determined for mating, chemotaxis, and gross movement. All experiments were performed at 20 to 22 degrees C. Results The median effective concentration values for halothane inhibition of mating (0.30 vol%-0.21 mM), chemotaxis (0.34 vol%-0.24 mM), and coordinated movement (0.32 vol% - 0.23 mM) were similar to the human minimum alveolar concentration (MAC; 0.21 mM). In contrast, halothane produced immobility with a median effective concentration of 3.65 vol% (2.6 mM). Other behaviors had intermediate sensitivities. Halothane's effects reached steady-state in 10 min for all behaviors tested except immobility, which required 2 h. Recovery was complete after exposure to 1 vol% halothane but was significantly reduced after exposure to immobilizing concentrations. Conclusions Volatile anesthetics selectively disrupt C. elegans behavior. The potency, time course, and recovery characteristics of halothane's effects on three behaviors are similar to its anesthetic properties in vertebrates. The affected nervous system molecules may express structural motifs similar to those on vertebrate anesthetic targets.

Sign in / Sign up

Export Citation Format

Share Document